Mechanical pencil



June 17, 1941. L. J. MOST MECHANICAL PENCIL Filed March 30, 1940INVENTOR BY v LA O EY Patented June 17, 1941 UNITED STATE-S PATENTOFFICE 2,245,805 MECHANICAL PENCIL Lucifer J. Most, Hudsoncounty, N. J.ApplicationMarch30, 1940, Serial No. 326,859 kwarms. (C1. 12o-fis) Myinvention relates to mechanical pencils and has reference particularlyto themeans for actuating the lead. 'The leads used in this' type ofmechanical pencil have a very' limitedcros's-sectional area'and'theirtotal massor weight is rather slight. It,`therefore,'becomes necessaryto provide means forinsuring the engagement of the lead with the' means'for actuating it at the time'the engagement lis'to take plac betweenthem, for gravity'alone is not sufficient' to' insure such engagement.Other objects of the invention will be pointed out hereinafter,v or willbe apparent to one skilled in the art from the disclosure therein.

In the appended drawing'iorming part of this application, Figure '1 visanenlarged vertical 'section online I-I, Figure'2 through the lower endof a mechanical pencil embodying my inven-r tion; no leads are showntobetter illustrate the invention.

Figure 2 is an enlarged crossesection on line 2 2, Figure`1.

Figure '3 is a similar section `on line 3-3, Figure 1. v 1

Figure 4 is an enlarged section on line 4-4, Figure 2 yof the tip end.

Figure 5 is an enlarged top end view of the interiorly threaded membershowingits engagement with a lead.

Figure 6 is an enlarged section on linev 6ft-6, Figure 5, and

Figure '7 is a view similar to that of Figure 5, showing the interiorlythreaded member provided for a lead of different crossfsection .thanthat shown in the .other figures.Y

Referringto the 'iigures,` I0 isa .barrel which terminates with a tip IIcoupled withv the barrel to participate in all the movements thereof.The tip I I is provided at its eXtremitywith a bore I2 .of a circularcross-section to frictionallyengage a lead fed therethrough. As shownthe tip end of the bore is splitteobtain the'frictional Contact but anyVother suitable means for that purpose maybe used. The bore I2 entersinto an enlarged circular bore I3 in which is mounted revolubly a tubeI4. The upper'portion of said tube is revolubly mounted in a bushing I5keyed to the barrel, as indicated at I6. The upper end of the tube I4enters an enlarged recess I'I inthe bushing and thereat carries anexterior gear I8 constrained to revolve With the tube. lower end thetube I4 carries within an interiorly threaded member I9, alsoconstrained to revolve with the tube.

A pinion -20 revolubly mounted inthe bushing I5 is in mesh with theexterior gear I8 and an interior gear 2I formed in a ring 22. The ring22 is coupled to a magazine tube 23 to revolve therewith.

Mounted within the tube I4 is a tube 24 which At thel perfnits the tubeI4l to revolve freely about it. The upper end of the tube 24 projectsout ofthe tube I4 and thereat carries a washer 25 rmly secured to theexterior'end of the tube 24, and also' firmly secured in the enlargedrecess I'I of the bushing I5. The washer 25 also serves as means forpreventing longitudinal displacement of the pinion 20 in the bushing.The lower end 26 of the tube 24 isswedged to form a lead guide 'of' the'desiredcross-sectional shape thatv Will by its contour prevent a lead ofcooperative crossvsectional contour from turning therein Whilepermitting the lead to move longitudinally. In this particular case, thecontour of the lead guide 26 is'triangular and "itis inalignment withthe threaded member and thebore I2, which bore also forms a frictionallead guide below the threaded member. The diameter of the bore I2 isSlightly less'than the diameter of the circle inscribng the edgesof'thelead.

.Positioned Within the magazine tube 23 is a washer121, which forms thebottom of said tube and with which it forms' the magazine for leads. Thewasher is shapedto facilitate the movement of the leads fro-m themagazine into the tube 24 'from where it enters the swedged end 26 ofsai'dtube, which swedged end constitutes the lead guide leading tothethreaded member I. This Washer 21 maybe coupled to the magazine tube23, Aor if desired, free thereof and coupled to the washer 25. In eitherarrangement it will perform the function described.

As'willbe' seen from Figures 1 and 4, the interiorly threaded memberwith its tube I4 by which it is driven fare so proportioned thatwhen thepencilis assembled, the lower end of the threadedmember bears on thebottom of the bore'v I3 in they tip. The longitudinal'movement of Ythethreaded member and the tube is prevented by the washerv 25' in therecess I'I and the contact -of the lower end of the swedged end 26 withthe upper face of the threaded member I9. 'To insure a positiveengagement of a'lead 28 with theinteri'orly threaded member I9, Iprovide notches 29l in theupper end of the threaded memben'th-atis, .theface adjacent tothe lead gui'de2i whichl guides a lead from the magazineor tube 24.to the threaded member I9. /These notches '29 are cutradiallyinthe wall of the threadedmember I9 and the number of thosenotches corresponds to the number of Iangles lthe leadihas. In thisparticular case, the lead is shown triangular, and'therefore threenotches haveV been cut. The width ofthe notches a-re such that theywould easily accommodate that portion ofthe' lateral surface .of thelead which isto be engaged bythe threads of the member I9.

the magazine l 2 3 revolved relatively to the barrel I0, the ring-221srevolved therewith, causing the interior gear I9 to turn the pinion 2B,Which in turn revolves the gear I8 and therewith the tube I4, whichcarries the interiorly threaded member I9. The bore I2 which forms thefrictional lead guide in the tip and the swedged end 26 which also formsa lead guide above the threaded member, are stationary, being coupled tothe barrel as previously described. In consequence of the rotation ofthe from turning in the guide but permitting the lead y to movelongitudinally, a second lead guide of threaded member I9 relatively tothe lead guides I2 and 26, the notches 29Y of the threaded member willintermittently register with the adjacent angular portions or the leadguide above the threaded member, thereby permitting the angular portion3| oi a lead ready to engage the threaded member I9 to enter into thenotches 29, through an axial depth of the said notches 2Q. This axialdepth must be at least that of a complete convolution of a thread. Inconsequence of this engagement of the lead portions 3l with the cut awayportions in the thread 30 a positive engagement takes place and thefurther rotation of the threaded member I9 causes the threads to cutinto the portion of the lead which lies in the notches Within thethreaded part 30.

I By this means I provide a positive engagement between the threadedmember and the lead coming thereinto and insure the progress of saidlead from the lead guide 26 through the threaded and thereafter throughthe lead reason for cutting those notches across the face of thethreaded member is the fact that the Wall thickness of the interiorlythreaded member is very small and to make those notches only within thedepth of the thread 30 of the threaded member is impractical.

The frictional lead guide formed by the bore I2 in the tip comes intoplay only when a lead fed by the threaded member leaves the lead guide26. It is then that its frictional engagement with the lateral edges ofthe lead therein prevent its turning when the threaded member is turned,thereby enabling the feeding out of a lead portion from the threadedmember. The piece of the lead that may be still engaged in thefrictional lead guide I2 is `forced out by a lead following it throughthe threaded member. 'Ihe threaded portion of the lateral surface of thelead provides a better frictional engagement between the lead and theyielding bore forming the frictional lead guide I2 in the tip than asmooth lead surface.

In Figure 7, the threaded member I9 is shown with notches 29 toaccommodate a lead of oval cross-section. It is evident that the leadguides will also be of oval cross-section, and the registration oi saidnotches 29 with the longer axis of the oval will permit the lead toenter into the threaded member and provide means for a positiveengagement between the lead and the threaded member.

It is self-evident that if the cross-section of the lead pencil ispolygonal as distinguished from the triangular, the number of notcheswill correspond thereto. Furthermore, for an oval lead pencil, as shownin Figure 7, four notches may be provided, and for a triangular lead asshown in Figure 5, six notches may be provided, in which case theregistration between the cooperating parts of the guide and threadedmember will take place at shorter intervals.

circular cross-section for frictionally engaging a Vlead coming from thethreaded member to prevent its turning in the second guide, and meansfor turning the threaded member relatively to the guides.

2. In a mechanical pencil, an interiorly threaded member for engaging alead directly, a lead guide for directing a lead to the member andhaving means inherent to its shape for preventing a lead shaped tocooperate with the guide from turning in the guide but permitting thelead to move longitudinally, a second lead guide of circularcross-section for frictionally engaging a lead coming from the threadedmember to prevent the lead from turning in the second guide, and meansfor turning the threaded member relatively to the guides, said threadedmember having means in the end adjacent to the rst guide for positivelyengaging the entering end of lead before said end of lead is engaged bythe threads of the member.

3. In a mechanical pencil, an interiorly threaded member for engagingdirectly a predetermined portion of the lateral surface of a lead, alead guide for` directing a lead to the member and having means inherentto its shape for preventing a lead shaped to cooperate with the guidefrom turning in the guide but permitting the lead to movelongitudinally, a second lead guide of circular cross-section forfrictionally engaging the lead coming from the threaded member, saidfrictional engagement of the second guide with the lead prevents thelead from turning in the second guide, and means for turning thethreaded member relatively to the guides, said threaded member havingmeans for engaging the end por- 45 i tip provided with a lead outlet ofcircular cross- 5o section shape to frictionally engage a lead thereinto prevent the lead from turningV in the outlet, a threaded member inthe tip adjacent to the lead outlet, a tubular member housing thethread-ed member and coupled with it and rising above the same Withinthe tip, a second tubular member within the rst and revoluble relativelythereto, said second tubular member having a reduced portion inproximity of the threaded member shaped to form a lead Vguide havingmeans inherent to its shape for preventing a lead shaped to cooperatewiththe guide from turning in said .guide while permitting the lead tomove longitudinally, a lead vmagazine in the barrel having means fordirecting leads into the second tubular membennand motion transmissionmeans fromr the magazine to the first tubular member, said threadedmember having means in proximity of the reduced portion of the secondtubular member to permit a lead to enter thereinto before the threads ofsaid threaded member engage the lead therein. Y Y

LUCIFER J. MOST.

